<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <form id="computed">
        <!-- 双向绑定 = 单向数据绑定 + UI事件监听 -->
        <input type="text" v-model="msg">
        <h3>{{msg}}</h3>

    </form>
    <script type="text/javascript" src="vue.js"></script>
    <script>
        var com = new Vue({
            el:"#computed",
            data:{
                msg:"123",
            },
            computed:{
 
            },
            methods:{

            }
        })
    </script>
</body>
</html>